Diagonal fan

ABSTRACT

A diagonal fan for gaseous media has a diagonal impeller with a plurality of vanes, which are fastened on a carrier plate, and a guide device, adjoining the diagonal impeller in the axial direction on the outflow side, for increasing the pressure of the medium, with a plurality of guide vanes. The vanes of the diagonal impeller and/or the guide vanes of the guide device are three-dimensionally twisted. By means of an intake unit, the gaseous medium can be directed into the diagonal impeller. The intake unit and/or an exhaust unit, by means of which the gaseous medium can be directed out of the guide device, is, or are, provided as an exchangeable module and can be fastened on the diagonal fan by means of a fastening element.

CROSS REFERENCE TO PRIOR APPLICATION

This application claims the benefit of German Patent Application No. 10 2010 032 168.0, filed Jul. 23, 2010, which is incorporated by reference herein.

FIELD OF THE INVENTION

The invention refers to a diagonal fan, by means of which a flow medium, which consists of air or other gases, can be delivered from the inside diagonally outwards. Such fans can be installed at the start, inside, or at the end of pipelines, for example, wherein the field of application of the diagonal fan according to the invention is not limited just to use in pipeline systems.

BACKGROUND OF THE INVENTION

For example, pipe fans, which have an exhaust unit and an axially symmetrical intake unit, between which is fastened a motor with radial impeller attached, are known. In order to adapt the pipe fan to different cross sections of pipeline systems, for example, a large part of the housing of the pipe fan has to be exchanged in each case. Consequently, the transitions between the intake unit and the radial impeller are generally of a fluidically unfavorable design and have steps and larger gaps. These pipe fans generally have no guide devices, or only rudimentary guide devices, so that the flow medium which leaves the radial impeller can be straightened again only in an unsatisfactory manner and the efficiency of the pipe fan decreases further.

A pipe fan, in which a guide device for increasing the pressure of the flow medium adjoins the diagonal impeller in the axial direction, is known from DE 203 19 749 U1. The diagonal fan has a diagonal impeller with vanes which are fastened laterally on a carrier plate and on a cover plate. The flow medium flows in the axial direction into the fan and flows through the diagonal impeller and as a result also flows through the vanes in the diagonal direction.

Adapting to different cross sections of pipeline systems or to different fields of application is usually possible only by means of an individual construction, which leads to higher production costs. If different cross sections or fields of application are to be offered, the entire fan often has to be adapted, which can lead to high development costs. Furthermore, high storage costs result for the large number of different components which are required for the construction of the fans.

Diagonal fans which can be adapted to different line cross sections by means of an adapter are furthermore offered. These adapters are usually mounted on the diagonal fan on the inflow side and outflow side so that the overall size increases proportionally. Also, the adapters are not an integral component part of the diagonal fan, but rather are to enable removal of the diagonal fan—for maintenance purposes or cleaning purposes, for example—from the pipeline system without the adapters also having to be removed from the pipeline system.

SUMMARY OF THE INVENTION

Starting from this previously known prior art, the invention is based on the object of disclosing an improved fan which has a compact construction and can be used as universally as possible.

The diagonal fan according to the invention has a diagonal impeller with a plurality of vanes which are fastened on a carrier plate. A guide device for increasing the pressure of the medium adjoins the diagonal impeller in the axial direction on the outflow side. Furthermore, the diagonal fan has an intake unit which directs the gaseous medium into the diagonal impeller, and, if applicable, an exhaust unit which directs the gaseous medium out of the guide device. Intake unit and/or exhaust unit is, or are, provided as exchangeable modules. In this case, only the intake unit or only the exhaust unit can be provided as an exchangeable module. Alternatively to this, both the intake unit and the exhaust unit can also be provided as exchangeable modules in each case.

The vanes of the diagonal impeller and/or the guide vanes of the guide device have two-dimensionally curved surfaces which are characterized in that they can no longer be developed upon a purely two-dimensional plane of Euclidian geometry. In practice, such vane geometries are also referred to as three-dimensionally twisted vanes.

The fastening of intake unit and exhaust unit on the diagonal fan is carried out by means of at least one fastening element for the accurate positioning and mounting of the exchangeable modules. The fan, therefore, can already be easily manipulated even before installation into a pipeline system, for example, which in particular makes installation and alignment of the fan easier.

The modular design according to the invention of the diagonal fan enables a compact construction and universal use of the fan. The central components—being the diagonal impeller and the guide device, with motor installed if necessary—can be fluidically optimized so that high efficiency of the fan, and consequently also a reduced noise loading, can be realized. At the same time, as a result of the exchangeable modular components—being the intake unit and the exhaust unit—an economically favorable adaptation of the fan to different pipe cross sections or to different fields of application, for example, can be carried out without having to reconstruct and fluidically optimize the entire diagonal fan. The individual modular components can be fluidically optimized independently of each other and can be adapted to the central components in each case so that the transition between the intake unit and the diagonal impeller, for example, is carried out as smoothly and steplessly as possible.

By means of the invention, provision can be made for a complete diagonal fan with fluidically optimized air guiding, which, particularly as a result of the three-dimensionally twisted (two-dimensionally curved) vanes of the diagonal impeller or of the guide device, achieves high efficiency and, as a result, a very low energy consumption. As a result of the design of the three-dimensionally twisted (two-dimensionally curved) vanes, allowance can optimally be made for the different flow velocities and inflow directions particularly at the inlet and outlet of the vanes. At the same time, as a result of the modular design a compact fan of comparatively small construction and with low noise development is created.

The fastening elements between the modular components and the central components of the diagonal fan can have, for example, at least one adhesive connection or at least one welded connection. In the case of the welded connection, it can especially be an ultrasonic welded connection. The fastening element can preferably have at least one mechanical coupling element. Such a fastening can usually be produced in a permanently reliable and simple manner.

The mechanical coupling elements can have at least one screw connection, for example. In the case of such a screw connection, it is conceivable to provide a first screw for the fastening of the intake unit to a central component of the diagonal fan and a second screw for the fastening of the exhaust unit to the same component or to another central component of the diagonal fan. In contrast to this, use could also be made of only a single screw which can be formed with such length that a connection of intake unit, central component of the diagonal fan and exhaust unit is possible with this screw. For improving stability, provision can be made for a plurality of such screw connections in a circumferentially distributed arrangement on the diagonal fan, wherein especially five to six screw connections can be formed.

Furthermore, the mechanical coupling elements can also have at least one clamping band connection which can be provided alternatively to or in addition to the screw connection. For example, the guide device and the exhaust unit can have in each case an outwardly pointing flange which but against each other in the installed state. The two abutting flanges could be encompassed by a clamping band in this position and so be fastened in a manner in which they press against each other.

The mechanical coupling elements can also have at least one clip-in connection in addition to or alternatively to this. In this case, the exhaust unit and the intake unit, for example, can have in each case at least one clip-in lever which can be clipped into a corresponding recess or undercut of the guide device, for example. Fastening can consequently be carried out very quickly and without tools. For improving stability, provision can be made for a plurality of such clip-in levers in a circumferentially distributed arrangement. Instead of a plurality of individual clip-in levers, an encompassing locking ring could also be provided. In the case of the design of such a locking ring, a good seal between the central components and the modular components is furthermore possible, which additionally increases the efficiency of the diagonal fan.

Alternatively to or in addition to the aforesaid embodiments, provision can also be made for at least one threaded connection. In this case, either the guide device or the exchangeable module could have a female thread, and the corresponding other component would be formed with a matching male thread. This embodiment can be advantageous especially when no alignment of the intake unit, for example, has to be carried out, that is to say especially when this has a circular intake opening.

The fastening element can preferably be a component part of the housing of the guide device. The fastening element can especially be a component part of the housing outer wall of the guide device.

In one advantageous embodiment, the intake unit can be a component part of the housing of the diagonal impeller. The entire housing of the diagonal impeller can especially be realized by the intake unit. This embodiment enables a particularly compact construction of the diagonal fan, in which extremely favorable flow paths are possible. The power which is generated by the diagonal fan is therefore concentrated on a small area, as a result of which the efficiency of the fan also increases. Furthermore, the production costs can be further reduced.

The modular design of the diagonal fan according to the invention enables application in many different technical fields. In addition to use as a pipe fan, it is also conceivable, for example, to use the diagonal fan as a roof fan. For this purpose, the diagonal fan would have to be equipped only with a corresponding exhaust unit which protects the diagonal fan which is provided on a roof of a building against weather influences so that no rain water can penetrate into the diagonal fan. The size of the roof fan would correspond approximately to the size of a comparable diagonal fan which is designed as a pipe fan so that a very compact construction still results.

Also, a sound-insulated design of a pipe fan, for example, is possible in a comparatively simple way by the central components being equipped with a sound-insulated exhaust unit and a sound-insulated intake unit.

Both the vanes of the guide device and the vanes of the diagonal impeller can be of a profiled design so that the vanes, even outside of the optimum operating range, are more insensitive to inflow directions which deviate from the optimum. The profiling of the vanes can furthermore lead to a further increase of efficiency. The profiling of the vanes is an essentially steady increase of the vane cross section up to a maximum and an essentially steady decrease of the vane cross section after it. The maximum of the vane cross section can already lie very close to one of the vane edges, comparable to an aircraft wing.

The vanes of the guide device and/or the vanes of the diagonal impeller can preferably have rounded leading edges. In this case, the trailing edge of each vane can taper off.

Further advantages and features of the invention are to be gathered from the features which are additionally disclosed in the claims and also from the subsequent exemplary embodiments.

BRIEF DESCRIPTION OF THE DRAWING

The invention is described and explained in more detail in the following text based on the exemplary embodiments which are shown in the drawing. In the drawing:

FIG. 1 shows a section through a diagonal fan according to the invention with intake unit and exhaust unit for a pipe cross section of 150 millimeter diameter in each case,

FIG. 2 shows a section through a diagonal fan according to the invention with intake unit and exhaust unit for a pipe cross section of 200 millimeter diameter in each case,

FIG. 3 shows a detailed view of the fastening of the intake unit and of the exhaust unit on the housing of the guide device by means of a first screw connection,

FIG. 4 shows a detailed view of the fastening of the intake unit and of the exhaust unit on the housing of the guide device by means of a second screw connection,

FIG. 5 shows a detailed view of the fastening of the intake unit on the housing of the guide device by means of a clamping band connection,

FIG. 6 shows a detailed view of the fastening of the intake unit on the housing of the guide device by means of a threaded connection,

FIG. 7 shows a detailed view of the fastening of the exhaust unit on the housing of the guide device by means of a first clip-in connection with at least one clip-in lever,

FIG. 8 shows a detailed view of the fastening of the exhaust unit on the housing of the guide device by means of a second clip-in connection with an encompassing locking ring,

FIG. 9 shows a detailed view of the fastening of the intake unit and of the exhaust unit on the housing of the guide device by means of an adhesive connection,

FIG. 10 shows a detailed view of the fastening of the intake unit on the housing of the guide device by means of an ultrasonic welded connection,

FIG. 11 shows a section through a diagonal fan, designed as a roof fan, according to the invention, and

FIG. 12 shows a section through a sound-insulated diagonal fan, designed as a pipe fan, according to the invention.

DETAILED DESCRIPTION OF THE INVENTION

The diagonal fan 10 has a diagonal impeller 12 which is provided on the inflow side of the fan 10. On the outflow side of the diagonal impeller 12, a guide device 14 is formed and, adjoining this, a diffuser 16 is formed inside the fan 10. The diagonal impeller 12 in the present exemplary case is enclosed by an intake unit 18 which on one side forms the housing of the diagonal impeller 12 and on the other side is connected to a pipe 20 of a pipeline which is not additionally shown here. On the outflow side, the diffuser 16 is formed by an exhaust unit 22. The exhaust unit 22 on one side is fastened on the housing outer wall 24 of the guide device 14 and on the other side is connected to a pipe 26 of a pipeline which is not additionally shown either. In the present exemplary case, the diameter A of the two pipes 20, 26 is of equal size and amounts to 150 millimeters in each case.

The connection of the intake unit 18 to the pipe 20, in common with the connection of the exhaust unit 22 to the pipe 26, can be realized in any way known from the prior art. In the present exemplary case, the pipe 20 has been pulled over the intake unit 18, in the same way as in the case of the pipe 26 which has been pulled over the exhaust unit 22. In contrast to this, a flange connection or a connection by means of a sleeve, for example, would also be conceivable.

The gaseous flow medium which is forced through the fan 10 by means of the diagonal impeller 12 flows around a central interior space of the fan 10 which is inwardly delimited by the carrier plate 30 of the diagonal impeller 12 and by an intermediate casing 32 which is connected to the carrier plate 30 in a streamlined manner. The carrier plate 30 is curved in the axial direction on the outflow side so that this buts against the axially aligned intermediate casing 32 in a streamlined manner. The flow medium therefore flows past the carrier plate 30 and the intermediate casing 32 radially on the outside.

The diagonal impeller 12 has circumferentially distributed vanes 34 which by their one side are fastened on the carrier plate 30 and by their opposite other side are fastened on a cover plate 36. The vanes 34 in the present exemplary case are of a cross-sectionally profiled and three-dimensionally twisted (two-dimensionally curved) design. The inflow-side leading edge of the vanes 34 is oriented approximately perpendicularly to the flow direction of the flow medium which flows onto it and is provided with a rounding. The outflow-side trailing edge of the vanes 34 is also oriented approximately perpendicularly to the diagonal flow which leaves it on the outflow side.

The cover plate 36 of the diagonal impeller 12 widens a little on the inflow side so that the intake unit 18 can fit round the diagonal impeller 12 from the outside by an inlet nozzle 38 and a streamlined transition of intake unit 18 and diagonal impeller 12 can be achieved. Between the inlet nozzle 38 of the intake unit 18 and the cover plate 36 of the diagonal impeller 12, there is an annular gap 40 which on account of the stationary intake unit 18 and the rotating diagonal impeller 12 cannot be avoided. There is a further annular gap 42 between the outflow-side end of the cover plate 36 and the housing wall 44 of the intake unit 18. The annular gaps 40, 42 are formed narrow to the extent that there can be no development of an annular flow extending through the space 46 between diagonal impeller 12 and intake unit 18.

If necessary, provision could also be made for one or more sealing elements behind the annular gaps 40, 42 in order to prevent such an annular flow being able to develop. Alternatively to or in addition to this, provision could also be made for angled annular gaps which would constitute a flow labyrinth.

In contrast to the exemplary embodiment which is shown here, the cover plate 36 could also be dispensed with. The vanes of such a diagonal impeller in this case would only be fastened on the carrier plate of this. The outer limit in this case could be realized by an inlet nozzle of the intake unit, for example, which is extended further inwards and therefore on the outflow side.

The flow which leaves the diagonal impeller 12 then flows through the region of the guide device 14. In this section of the fan 10, stationary guide vanes 50 are arranged in a circumferentially distributed manner between the intermediate casing 32 and the housing outer wall 24. By means of the guide vanes 50, the flow which leaves the diagonal impeller 12 in a helical, diagonal direction is deflected into an axial flow direction. Just like the vanes 34 of the diagonal impeller 12, the guide vanes 50 in the present exemplary case are also of a profiled and three-dimensionally twisted (two-dimensionally curved) design.

In contrast to the exemplary embodiment which is shown here, the profiling in the vanes 34 and/or in the guide vanes 50 could also be dispensed with.

Located in the interior space 52 which is formed by the carrier plate 30 of the diagonal impeller 12 or by the intermediate casing 32 of the guide device 14 is a motor 54 which drives the diagonal impeller 12 by means of a shaft 56. The motor 54 is flanged on a motor mounting 58 which projects from the, intermediate casing 32 into the interior space 52.

The diffuser 16 is formed downstream of the guide device 14 on the outflow side of this. The diffuser 16 is constructionally realized by means of an annular flow passage, becoming larger on the outflow side, between the motor cover 60 and the housing wall 62 of the exhaust unit 22. The motor cover 60 is fastened on the intermediate casing 32 of the guide device 14 by means of a plurality of screws, which are not shown here, and closes off the interior space 52 on the outflow side.

The fastening of intake unit 18 and exhaust unit 22 on the housing outer wall 24 of the guide device 14 is realized by means of a fastening element 70 which in the present exemplary case has a plurality of screw connections 72 (see also FIG. 3), of which only two screw connections 72 are shown in the present exemplary case.

For this purpose, the housing outer wall 24 of the guide device 14 is equipped with a threadless screw dome 74 which is formed over the entire length of the housing outer wall 24. The housing wall 44 of the intake device 18 is equipped with a comparable screw dome 76. A further screw dome 78, which in contrast to the screw domes 74 and 76 is formed as a blind hole and has a smaller inside diameter, is located on the housing wall 62 of the exhaust unit 22. By means of a screw 80, all three components—being the intake unit 18, guide device 14 and exhaust unit 22—can be quickly and reliably fastened to each other by the screw 80 being screwed into the screw dome 78.

A plurality of such screw connections 72 should preferably be provided in a circumferentially distributed arrangement in the guide device 14, in the intake unit 18 and in the exhaust unit in order to enable a stable fastening. Provision may be made for altogether four or five screw connections 72, for example.

The intake unit 18 and exhaust unit 22 of the diagonal fan 10 are therefore designed as exchangeable modules and can be adapted to the respective connection circumstances. If the diagonal fan 10 is to be connected to a pipeline system with a larger pipe diameter, for example, the central components—being the diagonal impeller 12, guide device 14 and motor 54—can remain unaltered. Only the intake unit 18 and the exhaust unit 22 would have to be correspondingly adapted. A corresponding installation situation is shown in FIG. 2.

The diagonal fan 10.2 which is shown in FIG. 2 differs from the diagonal fan 10 which is shown in FIG. 1 only as a result of the different modular components, these being the intake unit 18.2 and exhaust unit 22.2. The intake unit 18.2 and exhaust unit 22.2 in the present exemplary case are designed so that a connection of the diagonal fan 10.2 to a pipeline system with two pipes 20.2 and 26.2 with a diameter B of 200 millimeters in each case is possible.

The housing wall 62.2 of the exhaust unit 22.2 is therefore curved less sharply in comparison to the housing wall 62 of the exhaust unit 22 so that the outflow-side discharge opening of the diagonal fan 10.2 is only slightly reduced in size. The fastening of the exhaust unit 22.2 on the housing outer wall 24 of the guide device 14 is again realized via a screw connection 72.

Compared with this, the housing wall 44.2 of the intake unit 18.2 lies in a comparable curvature with regard to the housing wall 44 of the intake unit 18. However, the inlet nozzle 38.2 is curved considerably more sharply than the inlet nozzle 38 in order to still enable a streamlined transition between the intake unit 18.2 and the diagonal impeller 12.

In contrast to the exemplary case which is shown here, the central components of the diagonal fan could also be equipped, for example, on the inflow side with the intake unit 18 with a smaller diameter A and on the outflow side with the exhaust unit 22.2 with a larger diameter B. The diameter of the pipeline system in this case would increase downstream of the diagonal fan. The diagonal fan could therefore at the same time also serve as an adapter for the connection of two pipes with different diameter or even cross section.

An alternative screw connection 72.4 is shown in FIG. 3. In the case of the screw connection 72,4, the intake unit 18.4 is fastened on the housing outer wall 24.4 of the guide device 14.4 by means of a screw 82. The exhaust unit 22.4 is fastened on the housing outer wall 24.4 of the guide device 14.4 by means of a further screw 82. For this, the intake unit 18.4 and the exhaust unit 22.4 have in each case a screw dome 84, 86 by means of which the screws are screwed into the housing outer wall 24.4 of the guide device 14.4.

In addition to the screw connections 72, 72.4, other fastening elements 70, which are shown in FIGS. 5 to 10, are also possible in principle.

According to FIG. 5, the intake unit 18.5 and the guide device 14.5 are fastened to each other by means of a clamping band connection 100. For this, the intake unit 18.5, on its outflow-side end face, has an approximately outwardly pointing flange 102. The guide device 14.5, on its inflow-side end face, also has an approximately radially outwardly pointing flange 104. The two flanges 102 and 104 but tightly against each other in the installed state and can be encompassed by a clamping band 106 and fastened to each other.

A comparable clamping band connection 100 could also be provided between the guide device 14.5 and the exhaust unit, A clamping band connection 100 can be advantageous especially when the pipe cross section, which is to be connected to the diagonal fan, is circular, so that the intake unit and the exhaust unit do not have to be exactly aligned.

In FIG. 6, a threaded connection 110 between intake unit 18.6 and the guide device 14.6 is shown. Such a threaded connection 110 is also ideal particularly in the case of circular pipe cross sections. The intake unit 18.6 in the present exemplary case is provided with a male thread 112, and the guide device 14.6 correspondingly has a female thread 114. The exhaust unit could also be fastened by such a threaded connection 110 on the guide device 14.6.

The fastening element 70 could furthermore also be designed as a clip-in connection 120. In FIG. 7, a clip-in connection 120 between the guide device 14.7 and the exhaust unit 22.7 is shown. The guide device 14.7, on its outflow-side end face, has a clip-in lever 122. This clip-in lever 122 can engage in an undercut 124 which is located on the inner wall of the exhaust unit 22.7. Whereas in FIG. 7 only a single clip-in connection 120 is shown, as a rule a plurality of clip-in connections 120 are arranged in a circumferentially distributed manner in order to enable a stable fastening of the exhaust unit 22,7 on the guide device 14.7.

A particularly stable and at the same time also satisfactorily sealing fastening can be realized via a clip-in connection 120.8 which is shown in FIG. 8, in which instead of the clip-in lever 122 an encompassing locking ring 122.8 is formed on the guide device 14.8. The exhaust unit 22.8 correspondingly has an encompassing undercut 124.8 in which the locking ring 122.8 can engage, In order to enable an exact alignment of the exhaust unit 22.8, the encompassing locking ring and the encompassing undercut could be broken in each case at at least one point so that fastening is possible only in a defined position of exhaust unit and guide device in relation to each other.

In FIG. 9, an adhesive connection 130 between the guide device 14.9 and the intake unit 18.9 or the exhaust unit 22.9 is shown. For this purpose, on its outflow-side end wall the housing wall 44.9 of the intake unit 18.9 has an annular tongue 132. The inflow-side end wall of the housing outer wall 24.9 of the guide device 14.9 has an annular groove 134 in conformance with this. The annular tongue 132 can be inserted into the annular groove 134 and adhesively fixed with a suitable adhesive. An annular tongue 136 is located on the outflow-side end wall of the housing outer wall 24.9 of the guide device 14.9. The inflow-side end wall of the housing wall 62.9 of the exhaust unit 22.9 correspondingly has an annular groove 138 into which the annular tongue 136 of the guide device 14.9 can be inserted and adhesively fixed.

In contrast to the exemplary embodiment which is shown here, the housing outer wall of the guide device could also have an annular tongue in each case or an annular groove in each case in both its end faces.

In FIG. 10, an ultrasonic welded connection 140 between an intake unit 18.10 and a guide device 14.10 is shown. For this, the intake unit 18.10, on its outflow-side end face, has an approximately radially outwardly pointing flange 142 with a welding projection 144. The guide device 14.10, on its inflow-side end face, also has an approximately radially outwardly pointing flange 146. By means of an ultrasonic welding process, the two flanges 142 and 146 can be fastened to each other.

The different fastening elements 70 in principle can be combined with each other. Also, the fastening between the intake unit and the guide device can be realized by means of a first fastening element 70 and the fastening of the guide device on the exhaust unit can be realized by means of a second fastening element 70.

In addition to the fastening elements 70 which are shown here, a screw connection 72 and 72.4, clamping band connection 100, threaded connection 110, clip-in connection 120 and 120.8, adhesive connection 130 and ultrasonic welded connection 140, are also further forms of fastening which are conceivable.

A further application possibility of a diagonal fan 10.11 according to the invention is shown in FIG. 11. The diagonal fan 10.11 is a roof ventilator which can be installed on the roof of a building, for example, in order to transport exhaust air from the building to the outside. The diagonal fan 10.11 differs from the diagonal fan 10.2 only on account of its exhaust unit 22.11. This exhaust unit 22.11 is not designed for connecting to a pipe, for example, rather the exhaust unit 22.11 constitutes a sealing element which prevents rain water, for example, being able to penetrate into the diagonal fan. For this, the housing wall 62.11 of the exhaust unit 22.11 has an approximately bell-shaped outer contour by means of which the flow medium which leaves the guide device is deflected and leaves the exhaust unit 22.11 in the direction of the roof surface, which is not shown here. The exhaust unit 22.11 closes off the diagonal fan 10.11 from the upper side as a result so that no rain water, dirt or snow can penetrate into the diagonal fan and the function of the diagonal fan 10.11 can also be ensured during adverse weather conditions.

In FIG. 12, a further application possibility of a diagonal fan 10.12 according to the invention is shown. The diagonal fan 10.12 is a pipe fan of sound-insulated design. For this, only an intake unit 18.12 which is equipped with sound insulation 150 has to be fastened on the guide device 14.4. The sound insulation 150 in this case can include a sound-absorbing material. The screw connection 72.4 (see also FIG. 4) serves as the fastening element 70 in the present exemplary case. The streamlined adaptation of intake unit 18.12 to the diagonal impeller 12 is realized by means of the inlet nozzle 38.12. In a comparable way, an exhaust unit 22.12 which is equipped with sound insulation 150 is also fastened on the guide device 14.

In the exemplary case which is shown in FIG. 12, the motor cover 60.12 has also been designed differently in comparison to the exemplary embodiments which are shown in FIGS. 1 and 2. In contrast to this, however, the motor cover 60 could also be used in a sound-insulated diagonal fan. 

1. A diagonal fan for gaseous media comprising: a diagonal impeller having a plurality of vanes, said vanes being fastened on a carrier plate, a guide device, adjoining the diagonal impeller in the axial direction on the outflow side for increasing the pressure of the medium, wherein the vanes of the diagonal impeller and/or the guide vanes of the guide device are three-dimensionally twisted, and an intake unit by means of which the gaseous medium can be directed into the diagonal impeller, wherein the intake unit and/or an exhaust unit, by means of which the gaseous medium can be directed out of the guide device, is, or are, provided as an exchangeable module and can be fastened on the diagonal fan by means of a fastening element.
 2. A diagonal fan according to claim 1, wherein the fastening element has at least one adhesive connection.
 3. A diagonal fan according to claim 1, wherein the fastening element has at least one welded connection, especially an ultrasonic welded connection.
 4. A diagonal fan according to claim 1, wherein the fastening element has at least one mechanical coupling element.
 5. A diagonal fan according to claim 4, wherein the mechanical coupling element has at least one screw connection, clip-in connection, threaded connection or clamping band connection.
 6. A diagonal fan according to claim 1, wherein the fastening element is a component part of a housing of the diagonal fan.
 7. A diagonal fan according to claim 1, wherein the intake unit is a component part of the housing of the diagonal impeller.
 8. A diagonal fan according to claim 1, wherein the diagonal fan is designed as a roof ventilator.
 9. A diagonal fan according to claim 1, wherein the diagonal fan is of a sound-insulated design.
 10. A diagonal fan according to claim 1, wherein the vanes of the diagonal impeller are profiled.
 11. A diagonal fan according to claim 1, wherein the vanes of the guide device are profiled.
 12. A diagonal fan according to claim 1, wherein the vanes of the diagonal impeller are fastened on the carrier plate and on a cover plate. 